src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <signal.h>
  19 #include <limits.h>
  20 #include <resolv.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <syslog.h>
  24 #include <stdbool.h>
  25 #include <sys/time.h>
  26 #include <sys/ioctl.h>
  27 #include <sys/socket.h>
  28 #include <netinet/in.h>
  29
  30 #include <net/if.h>
  31 #include <net/ethernet.h>
  32
  33 #include "odhcp6c.h"
  34
  35
  36 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  37                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  38 #define DHCPV6_CLIENT_PORT 546
  39 #define DHCPV6_SERVER_PORT 547
  40 #define DHCPV6_DUID_LLADDR 3
  41 #define DHCPV6_REQ_DELAY 1
  42
  43
  44 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  45                 const uint8_t transaction[3], enum dhcpv6_msg type);
  46
  47 static time_t dhcpv6_parse_ia(void *opt, void *end);
  48
  49 static reply_handler dhcpv6_handle_reply;
  50 static reply_handler dhcpv6_handle_advert;
  51 static reply_handler dhcpv6_handle_rebind_reply;
  52 static reply_handler dhcpv6_handle_reconfigure;
  53 static int dhcpv6_commit_advert(uint32_t elapsed);
  54
  55
  56
  57 // RFC 3315 - 5.5 Timeout and Delay values
  58 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  59         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, "<POLL>",
  60                         dhcpv6_handle_reconfigure, NULL},
  61         [DHCPV6_MSG_SOLICIT] = {true, 1, 120, "SOLICIT",
  62                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  63         [DHCPV6_MSG_REQUEST] = {true, 30, 10, "REQUEST",
  64                         dhcpv6_handle_reply, NULL},
  65         [DHCPV6_MSG_RENEW] = {false, 10, 600, "RENEW",
  66                         dhcpv6_handle_reply, NULL},
  67         [DHCPV6_MSG_REBIND] = {false, 10, 600, "REBIND",
  68                         dhcpv6_handle_rebind_reply, NULL},
  69         [DHCPV6_MSG_RELEASE] = {false, 1, 600, "RELEASE", NULL, NULL},
  70         [DHCPV6_MSG_DECLINE] = {false, 1, 3, "DECLINE", NULL, NULL},
  71         [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, "INFOREQ",
  72                         dhcpv6_handle_reply, NULL},
  73 };
  74
  75
  76 // Sockets
  77 static int sock = -1;
  78 static int urandom_fd = -1;
  79 static int ifindex = -1;
  80 static time_t t1 = 0, t2 = 0, t3 = 0;
  81
  82 // IA states
  83 static int request_prefix = -1;
  84 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE;
  85 static bool accept_reconfig = false;
  86
  87
  88
  89 int init_dhcpv6(const char *ifname, int request_pd)
  90 {
  91         request_prefix = request_pd;
  92         urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY);
  93         if (urandom_fd < 0)
  94                 return -1;
  95
  96         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  97
  98         // Detect interface
  99         struct ifreq ifr;
 100         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 101         if (ioctl(sock, SIOCGIFINDEX, &ifr))
 102                 return -1;
 103         ifindex = ifr.ifr_ifindex;
 104
 105         // Create client DUID
 106         size_t client_id_len;
 107         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 108         if (client_id_len == 0) {
 109                 ioctl(sock, SIOCGIFHWADDR, &ifr);
 110                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 111                                 DHCPV6_DUID_LLADDR, 0, 1};
 112                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 113                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 114         }
 115
 116         // Create ORO
 117         uint16_t oro[] = {htons(DHCPV6_OPT_DNS_SERVERS),
 118                         htons(DHCPV6_OPT_DNS_DOMAIN),
 119                         htons(DHCPV6_OPT_NTP_SERVER),
 120                         htons(DHCPV6_OPT_SIP_SERVER_A),
 121                         htons(DHCPV6_OPT_SIP_SERVER_D)};
 122         odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 123
 124
 125         // Configure IPv6-options
 126         int val = 1;
 127         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 128         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 129         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 130
 131         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 132                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 133         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
 134                 return -1;
 135
 136         return 0;
 137 }
 138
 139
 140 void dhcpv6_set_ia_na_mode(enum odhcp6c_ia_mode mode)
 141 {
 142         na_mode = mode;
 143 }
 144
 145
 146 void dhcpv6_remove_addrs(void)
 147 {
 148         size_t ia_na_len;
 149         uint8_t *odata, *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 150         uint16_t otype, olen;
 151         dhcpv6_for_each_option(ia_na, ia_na + ia_na_len, otype, olen, odata) {
 152                 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
 153                 set_rtnetlink_addr(ifindex, &addr->addr, 0, 0);
 154         }
 155 }
 156
 157
 158 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 159 {
 160         // Build FQDN
 161         char fqdn_buf[256];
 162         gethostname(fqdn_buf, sizeof(fqdn_buf));
 163         struct {
 164                 uint16_t type;
 165                 uint16_t len;
 166                 uint8_t flags;
 167                 uint8_t data[256];
 168         } fqdn;
 169         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 170                         sizeof(fqdn.data), NULL, NULL);
 171         fqdn.type = htons(DHCPV6_OPT_FQDN);
 172         fqdn.len = htons(fqdn_len - 4);
 173         fqdn.flags = 0;
 174
 175
 176         // Build Client ID
 177         size_t cl_id_len;
 178         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 179
 180         // Get Server ID
 181         size_t srv_id_len;
 182         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 183
 184         // Build IA_PDs
 185         size_t ia_pd_len;
 186         void *ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 187         struct dhcpv6_ia_hdr hdr_ia_pd = {
 188                 htons(DHCPV6_OPT_IA_PD),
 189                 htons(sizeof(hdr_ia_pd) - 4 + ia_pd_len),
 190                 1, 0, 0
 191         };
 192
 193         struct dhcpv6_ia_prefix pref = {
 194                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 195                 .len = htons(25), .prefix = request_prefix
 196         };
 197
 198         if (ia_pd_len == 0 && request_prefix > 0 &&
 199                         (type == DHCPV6_MSG_SOLICIT ||
 200                         type == DHCPV6_MSG_REQUEST)) {
 201                 ia_pd = &pref;
 202                 ia_pd_len = sizeof(pref);
 203         }
 204
 205         // Build IA_NAs
 206         size_t ia_na_len;
 207         void *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 208         struct dhcpv6_ia_hdr hdr_ia_na = {
 209                 htons(DHCPV6_OPT_IA_NA),
 210                 htons(sizeof(hdr_ia_na) - 4 + ia_na_len),
 211                 1, 0, 0
 212         };
 213
 214         // Reconfigure Accept
 215         struct {
 216                 uint16_t type;
 217                 uint16_t length;
 218         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 219
 220         // Request Information Refresh
 221         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 222
 223         // Prepare Header
 224         size_t oro_len;
 225         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 226         struct {
 227                 uint8_t type;
 228                 uint8_t trid[3];
 229                 uint16_t elapsed_type;
 230                 uint16_t elapsed_len;
 231                 uint16_t elapsed_value;
 232                 uint16_t oro_type;
 233                 uint16_t oro_len;
 234         } hdr = {
 235                 type, {trid[0], trid[1], trid[2]},
 236                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 237                         htons((ecs > 0xffff) ? 0xffff : ecs),
 238                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 239         };
 240
 241         struct iovec iov[] = {
 242                 {&hdr, sizeof(hdr)},
 243                 {oro, oro_len},
 244                 {&oro_refresh, 0},
 245                 {cl_id, cl_id_len},
 246                 {srv_id, srv_id_len},
 247                 {&reconf_accept, 0},
 248                 {&fqdn, fqdn_len},
 249                 {&hdr_ia_na, sizeof(hdr_ia_na)},
 250                 {ia_na, ia_na_len},
 251                 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
 252                 {ia_pd, ia_pd_len},
 253         };
 254
 255         size_t cnt = ARRAY_SIZE(iov);
 256         if (type == DHCPV6_MSG_INFO_REQ) {
 257                 cnt = 5;
 258                 iov[2].iov_len = sizeof(oro_refresh);
 259                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 260         } else if (!request_prefix) {
 261                 cnt = 9;
 262         }
 263
 264         // Disable IAs if not used
 265         if (type == DHCPV6_MSG_SOLICIT) {
 266                 iov[5].iov_len = sizeof(reconf_accept);
 267         } else if (type != DHCPV6_MSG_REQUEST) {
 268                 if (ia_na_len == 0)
 269                         iov[7].iov_len = 0;
 270                 if (ia_pd_len == 0)
 271                         iov[9].iov_len = 0;
 272         }
 273
 274         if (na_mode == IA_MODE_NONE)
 275                 iov[7].iov_len = 0;
 276
 277         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 278                 0, ALL_DHCPV6_RELAYS, ifindex};
 279         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 280
 281         sendmsg(sock, &msg, 0);
 282 }
 283
 284
 285 static int64_t dhcpv6_rand_delay(int64_t time)
 286 {
 287         int random;
 288         read(urandom_fd, &random, sizeof(random));
 289         return (time * (random % 1000)) / 10000;
 290 }
 291
 292
 293 int dhcpv6_request(enum dhcpv6_msg type)
 294 {
 295         uint8_t buf[1536];
 296         uint32_t timeout = UINT32_MAX;
 297         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 298
 299         if (retx->delay) {
 300                 struct timespec ts = {0, 0};
 301                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 302                 nanosleep(&ts, NULL);
 303         }
 304
 305         if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
 306                 timeout = 3;
 307         else if (type == DHCPV6_MSG_UNKNOWN)
 308                 timeout = t1;
 309         else if (type == DHCPV6_MSG_RENEW)
 310                 timeout = t2 - t1;
 311         else if (type == DHCPV6_MSG_REBIND)
 312                 timeout = t3 - t2;
 313
 314         if (timeout == 0)
 315                 return -1;
 316
 317         syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, timeout);
 318
 319         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 320
 321         // Generate transaction ID
 322         uint8_t trid[3];
 323         read(urandom_fd, trid, sizeof(trid));
 324         ssize_t len = -1;
 325         int64_t rto = 0;
 326
 327         do {
 328                 rto = (rto == 0) ? (retx->init_timeo * 1000 +
 329                                 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
 330                                 (2 * rto + dhcpv6_rand_delay(rto));
 331
 332                 if (rto >= retx->max_timeo * 1000)
 333                         rto = retx->max_timeo * 1000 +
 334                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 335
 336                 // Calculate end for this round and elapsed time
 337                 uint64_t round_end = round_start + rto;
 338                 elapsed = round_start - start;
 339
 340                 // Don't wait too long
 341                 if (round_end - start > timeout * 1000)
 342                         round_end = timeout * 1000 + start;
 343
 344                 // Built and send package
 345                 if (type != DHCPV6_MSG_UNKNOWN)
 346                         dhcpv6_send(type, trid, elapsed / 10);
 347
 348                 // Receive rounds
 349                 for (; len < 0 && round_start < round_end;
 350                                 round_start = odhcp6c_get_milli_time()) {
 351                         // Check for pending signal
 352                         if (odhcp6c_signal_is_pending())
 353                                 return -1;
 354
 355                         // Set timeout for receiving
 356                         uint64_t t = round_end - round_start;
 357                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
 358                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 359                                         &timeout, sizeof(timeout));
 360
 361                         // Receive cycle
 362                         len = recv(sock, buf, sizeof(buf), 0);
 363
 364                         if (!dhcpv6_response_is_valid(buf, len, trid, type))
 365                                 len = -1;
 366
 367                         if (len > 0) {
 368                                 uint8_t *opt = &buf[4];
 369                                 uint8_t *opt_end = opt + len - 4;
 370
 371                                 round_start = odhcp6c_get_milli_time();
 372                                 elapsed = round_start - start;
 373                                 syslog(LOG_NOTICE, "Got a valid reply after "
 374                                                 "%ums", (unsigned)elapsed);
 375
 376                                 if (retx->handler_reply)
 377                                         len = retx->handler_reply(type,
 378                                                 opt, opt_end, elapsed / 1000);
 379                         }
 380                 }
 381
 382                 // Allow
 383                 if (retx->handler_finish)
 384                         len = retx->handler_finish(elapsed / 1000);
 385         } while (len < 0 && elapsed / 1000 < timeout);
 386
 387         return len;
 388 }
 389
 390
 391 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 392                 const uint8_t transaction[3], enum dhcpv6_msg type)
 393 {
 394         const struct dhcpv6_header *rep = buf;
 395         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 396                         transaction, sizeof(rep->tr_id)))
 397                 return false; // Invalid reply
 398
 399         if (type == DHCPV6_MSG_SOLICIT) {
 400                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 401                                 rep->msg_type != DHCPV6_MSG_REPLY)
 402                         return false;
 403         } else if (type == DHCPV6_MSG_UNKNOWN) {
 404                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 405                         return false;
 406         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 407                 return false;
 408         }
 409
 410         uint8_t *end = ((uint8_t*)buf) + len, *odata;
 411         uint16_t otype, olen;
 412         bool clientid_ok = false, serverid_ok = false;
 413
 414         size_t client_id_len, server_id_len;
 415         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 416         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 417
 418         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata)
 419                 if (otype == DHCPV6_OPT_CLIENTID)
 420                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 421                                         &odata[-4], client_id, client_id_len);
 422                 else if (otype == DHCPV6_OPT_SERVERID)
 423                         serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 424                                         &odata[-4], server_id, server_id_len);
 425
 426         return clientid_ok && (serverid_ok || server_id_len == 0);
 427 }
 428
 429
 430 int dhcpv6_poll_reconfigure(void)
 431 {
 432         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 433         if (ret != -1)
 434                 ret = dhcpv6_request(ret);
 435
 436         return ret;
 437 }
 438
 439
 440 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
 441                 const void *opt, const void *end, uint32_t elapsed)
 442 {
 443         // TODO: should verify the reconfigure message
 444         uint16_t otype, olen;
 445         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 446         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 447                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 448                                 odata[0] == DHCPV6_MSG_RENEW ||
 449                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 450                         msg = odata[0];
 451
 452         t1 -= elapsed;
 453         t2 -= elapsed;
 454         t3 -= elapsed;
 455
 456         if (t1 < 0)
 457                 t1 = 0;
 458
 459         if (t2 < 0)
 460                 t2 = 0;
 461
 462         if (t3 < 0)
 463                 t3 = 0;
 464
 465         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL, elapsed);
 466         return msg;
 467 }
 468
 469
 470 // Collect all advertised servers
 471 static int dhcpv6_handle_advert(_unused enum dhcpv6_msg orig,
 472                 const void *opt, const void *end, _unused uint32_t elapsed)
 473 {
 474         uint16_t olen, otype;
 475         uint8_t *odata;
 476         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}};
 477
 478         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 479                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 480                         memcpy(cand.duid, odata, olen);
 481                         cand.duid_len = olen;
 482                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
 483                                 && odata[1] == DHCPV6_NoAddrsAvail) {
 484                         if (na_mode == IA_MODE_FORCE) {
 485                                 return -1;
 486                         } else {
 487                                 cand.has_noaddravail = true;
 488                                 cand.preference -= 1000;
 489                         }
 490                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
 491                                 && odata[1] == DHCPV6_NoPrefixAvail) {
 492                         cand.preference -= 2000;
 493                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 494                                 cand.preference >= 0) {
 495                         cand.preference = odata[1];
 496                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 497                         cand.wants_reconfigure = true;
 498                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 499                         struct dhcpv6_ia_hdr *h = (void*)odata;
 500                         uint8_t *oend = odata + olen, *d;
 501                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 502                                 if (otype == DHCPV6_OPT_IA_PREFIX)
 503                                         cand.preference += 2000;
 504                                 else if (otype == DHCPV6_OPT_STATUS &&
 505                                                 olen >= 2 && d[0] == 0 &&
 506                                                 d[1] == DHCPV6_NoPrefixAvail)
 507                                         cand.preference -= 2000;
 508                         }
 509                 }
 510         }
 511
 512         if (cand.duid_len > 0)
 513                 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
 514
 515         return -1;
 516 }
 517
 518
 519 static int dhcpv6_commit_advert(_unused uint32_t elapsed)
 520 {
 521         size_t cand_len;
 522         struct dhcpv6_server_cand *c = NULL, *cand =
 523                         odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
 524
 525         bool retry = false;
 526         for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
 527                 if (cand[i].has_noaddravail)
 528                         retry = true; // We want to try again
 529
 530                 if (!c || c->preference < cand[i].preference)
 531                         c = &cand[i];
 532         }
 533
 534         if (retry && na_mode == IA_MODE_TRY) {
 535                 // We give it a second try without the IA_NA
 536                 na_mode = IA_MODE_NONE;
 537                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
 538         }
 539
 540         if (c) {
 541                 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
 542                                 htons(c->duid_len)};
 543                 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
 544                 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
 545                 accept_reconfig = c->wants_reconfigure;
 546         }
 547
 548         odhcp6c_clear_state(STATE_SERVER_CAND);
 549
 550         if (!c)
 551                 return -1;
 552         else if (request_prefix || na_mode != IA_MODE_NONE)
 553                 return DHCPV6_STATEFUL;
 554         else
 555                 return DHCPV6_STATELESS;
 556 }
 557
 558
 559 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
 560                 const void *opt, const void *end, uint32_t elapsed)
 561 {
 562         dhcpv6_handle_advert(orig, opt, end, elapsed);
 563         if (dhcpv6_commit_advert(elapsed) < 0)
 564                 return -1;
 565
 566         return dhcpv6_handle_reply(orig, opt, end, elapsed);
 567 }
 568
 569
 570 static int dhcpv6_handle_reply(_unused enum dhcpv6_msg orig,
 571                 const void *opt, const void *end, uint32_t elapsed)
 572 {
 573         uint16_t otype, olen;
 574         uint8_t *odata;
 575         bool have_update = false;
 576
 577         t1 = t2 = t3 = 86400;
 578
 579         size_t ia_na_len, dns_len, search_len, sntp_ip_len, sntp_dns_len;
 580         size_t sip_ip_len, sip_fqdn_len;
 581         uint8_t *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 582         uint8_t *ia_end;
 583         odhcp6c_get_state(STATE_DNS, &dns_len);
 584         odhcp6c_get_state(STATE_SEARCH, &search_len);
 585         odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 586         odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 587         odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 588         odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 589
 590         // Decrease valid and preferred lifetime of prefixes
 591         size_t ia_pd_len;
 592         uint8_t *ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 593         dhcpv6_for_each_option(ia_pd, ia_pd + ia_pd_len, otype, olen, odata) {
 594                 struct dhcpv6_ia_prefix *p = (void*)&odata[-4];
 595                 uint32_t valid = ntohl(p->valid);
 596                 p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 597
 598                 uint32_t pref = ntohl(p->preferred);
 599                 p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
 600         }
 601
 602         // Decrease valid and preferred lifetime of addresses
 603         dhcpv6_for_each_option(ia_na, ia_na + ia_na_len, otype, olen, odata) {
 604                 struct dhcpv6_ia_addr *p = (void*)&odata[-4];
 605                 uint32_t valid = ntohl(p->valid);
 606                 p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 607
 608                 uint32_t pref = ntohl(p->preferred);
 609                 p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
 610         }
 611
 612         // Parse and find all matching IAs
 613         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 614                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 615                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 616                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 617                         time_t l_t1 = ntohl(ia_hdr->t1);
 618                         time_t l_t2 = ntohl(ia_hdr->t2);
 619
 620                         // Test ID and T1-T2 validity
 621                         if (ia_hdr->iaid != 1 || l_t2 < l_t1)
 622                                 continue;
 623
 624                         uint16_t stype, slen;
 625                         uint8_t *sdata;
 626                         // Test status and bail if error
 627                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 628                                         stype, slen, sdata)
 629                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2 &&
 630                                                 (sdata[0] || sdata[1]))
 631                                         continue;
 632
 633                         // Update times
 634                         if (l_t1 > 0 && t1 > l_t1)
 635                                 t1 = l_t1;
 636
 637                         if (l_t2 > 0 && t2 > l_t2)
 638                                 t2 = l_t2;
 639
 640                         // Always report update in case we have IA_PDs so that
 641                         // the state-script is called with updated times
 642                         if (otype == DHCPV6_OPT_IA_PD && request_prefix)
 643                                 have_update = true;
 644
 645                         time_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
 646
 647                         if (n < t1)
 648                                 t1 = n;
 649
 650                         if (n < t2)
 651                                 t2 = n;
 652
 653                         if (n < t3)
 654                                 t3 = n;
 655
 656                 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 657                         if (olen == 16)
 658                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 659                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 660                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 661                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 662                         uint16_t stype, slen;
 663                         uint8_t *sdata;
 664                         // Test status and bail if error
 665                         dhcpv6_for_each_option(odata, odata + olen,
 666                                         stype, slen, sdata) {
 667                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 668                                                 stype == NTP_SRV_ADDR))
 669                                         odhcp6c_add_state(STATE_SNTP_IP,
 670                                                         sdata, slen);
 671                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 672                                         odhcp6c_add_state(STATE_SNTP_FQDN,
 673                                                         sdata, slen);
 674                         }
 675                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 676                         if (olen == 16)
 677                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 678                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 679                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 680                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 681                         uint32_t refresh = ntohl(*((uint32_t*)odata));
 682                         if (refresh < (uint32_t)t1)
 683                                 t1 = refresh;
 684                 } else if (otype != DHCPV6_OPT_CLIENTID &&
 685                                 otype != DHCPV6_OPT_SERVERID) {
 686                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
 687                                         &odata[-4], olen + 4);
 688                 }
 689         }
 690
 691         if (opt) {
 692                 have_update |= odhcp6c_commit_state(STATE_DNS, dns_len);
 693                 have_update |= odhcp6c_commit_state(STATE_SEARCH, search_len);
 694                 have_update |= odhcp6c_commit_state(STATE_SNTP_IP,
 695                                 sntp_ip_len);
 696                 have_update |= odhcp6c_commit_state(STATE_SNTP_FQDN,
 697                                 sntp_dns_len);
 698                 have_update |= odhcp6c_commit_state(STATE_SIP_IP, sip_ip_len);
 699                 have_update |= odhcp6c_commit_state(STATE_SIP_FQDN, sip_fqdn_len);
 700                 size_t new_ia_pd_len, new_ia_na_len;
 701                 odhcp6c_get_state(STATE_IA_PD, &new_ia_pd_len);
 702                 odhcp6c_get_state(STATE_IA_NA, &new_ia_na_len);
 703                 have_update |= (new_ia_pd_len != ia_pd_len) ||
 704                                 (new_ia_na_len != ia_na_len);
 705         }
 706
 707         // Delete prefixes with 0 valid-time
 708         ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 709         ia_end = ia_pd + ia_pd_len;
 710         dhcpv6_for_each_option(ia_pd, ia_end, otype, olen, odata) {
 711                 struct dhcpv6_ia_prefix *p = (void*)&odata[-4];
 712                 while (!p->valid) {
 713                         ia_end = ia_pd + odhcp6c_remove_state(STATE_IA_PD,
 714                                         (uint8_t*)p - ia_pd, olen + 4);
 715                         have_update = true;
 716                 }
 717         }
 718
 719
 720         // Delete addresses with 0 valid-time
 721         ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 722         ia_end = ia_na + ia_na_len;
 723         dhcpv6_for_each_option(ia_na, ia_end, otype, olen, odata) {
 724                 struct dhcpv6_ia_addr *p = (void*)&odata[-4];
 725                 while (!p->valid) {
 726                         ia_end = ia_na + odhcp6c_remove_state(STATE_IA_NA,
 727                                         (uint8_t*)p - ia_na, olen + 4);
 728                         have_update = true;
 729                 }
 730         }
 731
 732         return have_update;
 733 }
 734
 735
 736 static time_t dhcpv6_parse_ia(void *opt, void *end)
 737 {
 738         uint32_t timeout = UINT32_MAX; // Minimum timeout
 739         uint16_t otype, olen, stype, slen;
 740         uint8_t *odata, *sdata;
 741
 742         // Update address IA
 743         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 744                 if (otype == DHCPV6_OPT_IA_PREFIX) {
 745                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
 746                         if (olen + 4U < sizeof(*prefix))
 747                                 continue;
 748
 749                         olen = sizeof(*prefix); // Normalize length
 750                         uint32_t valid = ntohl(prefix->valid);
 751                         uint32_t pref = ntohl(prefix->preferred);
 752
 753                         if (pref > valid)
 754                                 continue;
 755
 756                         // Search matching IA
 757                         struct dhcpv6_ia_prefix *local = NULL;
 758                         size_t pd_len;
 759                         uint8_t *pd = odhcp6c_get_state(STATE_IA_PD, &pd_len);
 760                         dhcpv6_for_each_option(pd, pd + pd_len,
 761                                         stype, slen, sdata)
 762                                 if (!memcmp(sdata + 8, odata + 8,
 763                                                 sizeof(local->addr) + 1))
 764                                         local = (void*)&sdata[-4];
 765
 766                         if (local) { // Already know that IA
 767                                 local->preferred = prefix->preferred;
 768                                 local->valid = prefix->valid;
 769                         } else { // New IA
 770                                 odhcp6c_add_state(STATE_IA_PD, prefix, olen);
 771                         }
 772
 773                         if (timeout > valid)
 774                                 timeout = valid;
 775
 776                         if (prefix->valid == 0) // We probably lost that prefix
 777                                 odhcp6c_add_state(STATE_IA_PD_LOST,
 778                                                 prefix, olen);
 779                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
 780                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
 781                         if (olen + 4U < sizeof(*addr))
 782                                 continue;
 783
 784                         olen = sizeof(*addr); // Normalize length
 785                         uint32_t pref = ntohl(addr->preferred);
 786                         uint32_t valid = ntohl(addr->valid);
 787
 788                         if (pref > valid)
 789                                 continue;
 790
 791                         // Search matching IA
 792                         struct dhcpv6_ia_addr *local = NULL;
 793                         size_t na_len;
 794                         uint8_t *na = odhcp6c_get_state(STATE_IA_NA, &na_len);
 795                         dhcpv6_for_each_option(na, na + na_len,
 796                                         stype, slen, sdata)
 797                                 if (!memcmp(sdata, odata, sizeof(local->addr)))
 798                                         local = (void*)&sdata[-4];
 799
 800
 801                         if (local) { // Already know that IA
 802                                 local->preferred = addr->preferred;
 803                                 local->valid = addr->valid;
 804                         } else { // New IA
 805                                 odhcp6c_add_state(STATE_IA_NA, addr, olen);
 806                         }
 807
 808
 809                         if (timeout > valid)
 810                                 timeout = valid;
 811
 812                         if (set_rtnetlink_addr(ifindex, &addr->addr,
 813                                         pref, valid) == -EADDRNOTAVAIL) {
 814                                 dhcpv6_request(DHCPV6_MSG_DECLINE);
 815                                 raise(SIGUSR2);
 816                         }
 817                 }
 818         }
 819
 820         return timeout;
 821 }